1. Field of the Invention
The present invention generally relates to a transmission arrangement for all terrain vehicles. More particularly, the present invention relates to a cover and shaft supporting arrangement for such a transmission.
2. Description of the Related Art
All terrain vehicles have begun employing variable speed transmissions. Such variable speed transmissions utilize a drive pulley that may be coupled to a crankshaft of an engine through any suitable mechanism. The drive pulley, in turn, may be connected to a driven pulley through a belting arrangement such that as the belt rotates under the force of the drive pulley, the driven pulley is also rotated.
In some vehicles, the driven pulley may be carried upon an output shaft that extends into a crankcase of the all terrain vehicle. This output shaft is often carried by two sets of bearings carried within the crankcase and arranged along the output shaft such that the output shaft is cantilevered outwards to receive the driven pulley. The drive pulley however may be carried on a driveshaft that is carried on one end by a set of bearings that are supported by the crankcase. In such constructions, the driveshaft is also cantilevered. Accordingly, the wall that supports the bearings must be of increased thickness and heft. Moreover, the driveshaft experiences a high level of bending forces as the driveshaft spins the drive pulley.
Thus, it is desired to have a crankcase cover and bearing supporting arrangement capable of having a reduced weight while not significantly reducing the strength of such a cover assembly. Moreover, the driveshaft should be supported in a manner in which the driveshaft does not experience the increased bending forces.
Accordingly, one aspect of the present invention is an all terrain vehicle comprising a frame with an engine compartment defined within the frame. An engine is mounted within the engine compartment. The engine comprises a crankcase, a transvsersely-extending crankshaft and a transmission connected to the crankshaft. The transmission comprises a drive pulley, a driven pulley and a flexible loop connecting the drive pulley to the driven pulley. A transmission inputs connected to the drive pulley with a first bearing supporting a first end of the input shaft and positioned proximate the crankcase. A second bearing supports a second end of the input shaft with a bearing bracket carrying the second bearing. A bearing retaining portion is formed on the bearing bracket with the bearing positioned within the bearing retaining portion. The bearing bracket having at least one arm that extends between the crankcase and the bearing retaining portion.
Another aspect of the present invention involves a transmission cover for an all terrain vehicle. The transmission cover comprises a mounting bracket and a cover member. The mounting bracket comprises a bearing support. The bearing support has an aperture with a center axis. The mounting bracket also has at least one arm with a first portion extending radially away from the bearing support in a direction generally normal to the center axis and a distal second portion extending in a direction generally parallel to the center axis. The cover member is preferably sized and configured to encase the mounting bracket.